Decibel Limits: San Mateo vs South San Francisco
How do decibel limits rules compare between San Mateo, CA and South San Francisco, CA?
San Mateo and South San Francisco have similar restriction levels.
San Mateo, CA
San Mateo County
County Code 4.88.330 sets exterior noise limits at residences, schools, hospitals, churches and libraries on a sliding scale by how long the noise lasts in an hour. Daytime (7 a.m.-10 p.m.) limits run from 55 dBA (30 min/hr) up to 75 dBA (instantaneous max); nighttime (10 p.m.-7 a.m.) limits are 5 dBA lower, from 50 to 70 dBA.
View full San Mateo rules →South San Francisco, CA
San Mateo County
County Code 4.88.330 sets exterior noise limits at residences, schools, hospitals, churches and libraries on a sliding scale by how long the noise lasts in an hour. Daytime (7 a.m.-10 p.m.) limits run from 55 dBA (30 min/hr) up to 75 dBA (instantaneous max); nighttime (10 p.m.-7 a.m.) limits are 5 dBA lower, from 50 to 70 dBA.
View full South San Francisco rules →Key Facts Comparison
| Fact | San Mateo | South San Francisco |
|---|---|---|
| Code section | County Code 4.88.330 (Table I) | County Code 4.88.330 (Table I) |
| Daytime 30-min limit | 55 dBA (7 a.m.-10 p.m.) | 55 dBA (7 a.m.-10 p.m.) |
| Nighttime 30-min limit | 50 dBA (10 p.m.-7 a.m.) | 50 dBA (10 p.m.-7 a.m.) |
| Daytime max (not to exceed) | 75 dBA | 75 dBA |
| Nighttime max (not to exceed) | 70 dBA | 70 dBA |
Highlighted rows indicate differences between cities.
San Mateo FAQ
What is the nighttime noise limit in unincorporated San Mateo County?
Under 4.88.330, nighttime exterior limits (10 p.m.-7 a.m.) start at 50 dBA for noise lasting 30 minutes of the hour, rising in steps to a 70 dBA level that is never to be exceeded.
Where is the noise measured?
At the exterior of the affected residence, school, hospital, church or public library - the receiving property - not at the source of the noise.
South San Francisco FAQ
What is the nighttime noise limit in unincorporated San Mateo County?
Under 4.88.330, nighttime exterior limits (10 p.m.-7 a.m.) start at 50 dBA for noise lasting 30 minutes of the hour, rising in steps to a 70 dBA level that is never to be exceeded.
Where is the noise measured?
At the exterior of the affected residence, school, hospital, church or public library - the receiving property - not at the source of the noise.
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